Stabilized soap



Patented Nov. '12, 1940 1 UNITED STATES PATENT OFFICE g STABILIZED SOAP Robert L. Sibley, Nitro, W. Va. assignor to Monsanto poration of Delaware No Drawing. a Application September 24, 1936,

Serial No. 102,332

The present invention relates to the manuiacture of soap and soap products, and more par- Chemical Company, St. Louis, Mo., a cor- 5 Olaims. (C1. 23-250) short time.

One of the objects of the greatest inventionis to inhibit or retard this deteriorating,

action by incorporating in the soap stock, or soap, or in one or more of the ingredients used in the manufacture ther eof, a small quantity of one or more of the preferred class of substances herein disclosed.

In accordance with the present invention it has been found that on incorporating in an unstable soap a relatively small proportion of a biguanide compound, as for example biguanide and its substitution products, salts and derivatives thereof, its tendency to develop rancidlty is markedly lessened and the treated soap rendered substantially stable.

More particularly the present invention comprises the use in the stabilization of soap and soap products of biguanides possessing the gen-v eral formula of wherein R is hydrogen or an organic radical, as for example an alkyl, aryl, aralkyl and alicyclic radical.

In practicing the present invention, the preferred stabilizing agent may be introduced at any the stabilizing agent may be incorporated into the dry soap in the well-known crutching process.

As one method of testing the stabilizing properties of the preferred class of materials, the following procedure was employed:

A substantially neutral soap w as prepared by saponifying a. mixture of substantially three parts of an edibletallow and substantially one part of cocoanut oil with sodium hydroxide. Substantially 0.1% based on the weight of the soap (0.005 gram) ,of one of thepreferred stabilizers 6 was incorporated therein by a suitable means. Five grams of the treated soap were placed in a 250 c. c. iodineflask, a piece of filter paper saturated with water was torn to small pieces and placed in the flask. The flask was then tightly 10 stoppered and placed in an oven maintained at a constanttemperature of 50 C. At the end ofeach day the stopper was removed and any odor indicative of rancidlty noted. Similar tests were carried out with the same soap but to which no 15 stabilizer was added, and the period of stability compared as hereinafter set iorth.

As specific examples andjas specific embodiments of the present invention, but in no sense to be understood as limitative of the scope of the 20 invention, the ,following biguanide compounds were incorporated in a soap of the above composition and tested in the manner described. At the end of the test period indicated in the table below, the soaps containing the preferred ma-% terials had remained stable, having failed to develop rancidlty, and undoubtedly'would have reu mained stable for much longer periods of time.

Table I v Stabilizing en Stabilizing agent la ed 6n g? the weight or the soap Per cent Days Mono ortho tollyl biguanide..- 0. 1 20 Alpha dipheny biguanidem" 0. 1 16 Mono p-phenetidyl bi 0. 1 16- Mono ortho biphenyl do 0. 1 l3 Mono phenyl biguanide hydrochloride 0. 1 l2 Mono phenyl biguanide 0. 1 12 0 Mono xylyl biguanide 0. 1 l8 Mono xylyl biguanide hydrochloride 0. 1 18 Mono ortho anisidyibi anidehydrochlorid 0. l 18 Mono ortho anisidyl b guanid 0. l 18 Mono para biphenyl biguanide-. 0. 1 18 Blank None 4 Another important advantage in the use of the preferred stabilizers isthe fact that, while they are exceptionally strong stabilizers against rancidity formation, they do not generally discolor the soap on exposure to sunlight. Many of the 50 stabilizers heretofore employed in the soap industry were exceptionally bad discolorers of soap. One specific example is diphenyl amine. The preferred materials of the present inventionfor the most part not only do not discolor the soap 55 on vent its butverymarksdlym to sunlight. discoloration when so exposed. Thus,

soaps prepared from-edible tallow and cocoanut oil as described above and containing 0.1%, based on the weight'of, the soap, of mono'ortho tolyl biguanide, alpha diphenyl biguahide, mono phenyl biguanide hydrochloride, mono phenyl biguanide, mono .xylyl biguanide. mono xylyl biguanide hydrochloride, mono ortho anisidyl biguanide hydrochloride, mono ortho anisidyl biguanide and mono ortho phenetidyl biguanide respectively showed no discoloration when exposed to direct sunlight for one hundred hours.

From the above data it is shown that the preferred class of compounds exceptional stabilizing properties when incorporated in soap and soap products. s 7

Other biguanide' compounds which have been employed to good advantage in the. practice of this invention include alpha naphthyl biguanide, alpha naphthyl biguanide hydrochloride and biguanide hydrochloride. Included within the scope of this invention is the use of the analogues in the manufacture thereof, for effecting the desired result, may be varied, but in general it will be found that good results may be obtained by adding on a weight from 0.01% 1.0%

. specification.

of the stabilizing agent to the soap or soap stock.

The present invention is limited solely by the following claims attached hereto as part of the What is claimed is: a t

1. A soap comprising a water soluble salt of a higher fatty acid stabilized against deterioration'and development of rancidity by having in- ,corporated therein more than 0.01% of a mono aryl substituted bizuanide.

2. A soap comprising a water soluble salt of a higher fatty acid stabilized ag nst deterioration and development of rancidity y having incurporated therein more than 0.01% of an aryl hydrocarbon substituted biguanide said aryl substituent being selected from the benzene, biphenyl and naphthalene series.

s. a soap comprising a watersoluble salt of a higher fatty acid stabilized against deterioration and development of rancidity by having incorporated therein more than 0.01% of mono ortho tolyl blguanide.

4. A soap comprisinga water soluble salt of a higher acid stabilized against deterioration and development of rancidity by having incorporat-' ed therein more than 0.01% of mono xylyi biguanide.

5. A soap comprising a water soluble salt of a higher fatty. acid stabilized against deterioration and development of rancidity by having incorporatedtherein more than 0.01% of mono phenyl biguanide.

aonn'm' 1;. BIBLEY. 

